docs: def _determine_minimizer(self):
          """
          Determine the most suitable minimizer by the presence of bounds or
          constraints.
          :return: a subclass of `BaseMinimizer`.
          """
          if self.constraints:
              return SLSQP
          elif any([bound is not None for pair in self.model.bounds for bound in pair]):
              # If any bound is set
              return LBFGSB
          else:
              return BFGS